1. Field of the Invention
This invention relates to the preparation of polyurethanes including solid, non-cellular, and foamed urethanes both rigid and flexible.
2. Description of the Prior Art
It is known to manufacture polyurethanes using organic zirconium compounds as catalysts from U.S. Pat. No. 3,673,159. In this reference, there is disclosed the use of zirconium alcoholates or phenylates. It is also known from U.S. Pat. No. 4,122,046 to utilize organic compounds containing zirconium as a catalyst for the polymerization of acrylamide or mixtures of acrylamide and at least one ethylenically unsaturated monomer copolymerizable therewith.
It is also known from U.S. Pat. No. 4,087,402 and U.S. Pat. No. 4,216,107 to utilize organic titanium compounds to reduce viscosity in liquid polymers whether filled with inorganic fillers or unfilled.